Solvatochromism of Heteroaromatic Compounds: X. 2-Phenylpyrrolide Anion

2-Phenylpyrrolide anion was obtained in high-polarity media containing MeONa as an ionizing agent. The bathochromic shift of the long-wave absorption band in going from the neutral to deprotonated form is explained by the difference in the molecular orbital characteristics of the parent molecule and the anion, as well as the by change in the equilibrium conformation on deprotonation. According to ab initio calculations, the conformational rearrangement contributes partly to the observed shift; the greatest contribution is from the destabilization of the highest occupied molecular orbital.